1. Field of the Invention
The present invention relates to the delivery of a stent and other devices into the myocardium of a patient, and more particularly, to a stent delivery system to provide a bypass through the myocardium from the left ventricle into a coronary artery.
2. Description of the Related Art
Coronary arteries as well as other vessels frequently become clogged with plaque that at the very least impairs the efficiency of the heart""s pumping action and can lead to heart attack and death. One conventional treatment for clogged coronary or other arteries is a bypass operation wherein one or more venous segments are inserted between the aorta and the coronary artery. The inserted venous segments or transplants act as a bypass of the clogged portion of the coronary artery and thus provide for a free or unobstructed flow of blood to the heart.
Such coronary artery bypass surgery, however, is expensive, time-consuming and traumatic to the patient. Hospital stays subsequent to the surgery and convalescence are prolonged.
A new coronary artery bypass technique is disclosed in U.S. Pat. No. 5,429,144. That technique utilizes a stent made of a biocompatible material and comprises steps of moving the stent in a collapsed configuration through a blood vessel of a patient""s vascular system to the patient""s heart, inserting the stent in the patient""s myocardium, and upon disposition of the stent in the myocardium, expanding the stent from the collapsed configuration to a substantially tubular expanded configuration so that a blood flow path is formed at least partially through the myocardium.
One problem with the coronary artery bypass method providing a stent through the myocardium of the heart is how to get the stent into the myocardium. U.S. Pat. No. 5,429,144 describes a percutaneous approach wherein the stent is brought to the myocardium through the patient""s vasculature on the distal end of a catheter, and advanced into the myocardium over a guidewire. One particular challenge is how to make an angled bend in the guidewire to puncture through the wall of the vessel and into the myocardium.
Another problem with this approach is that catheters delivering the guidewire, stent or other devices to be provided into the myocardium are conventionally guided to the puncture point through the blockage in the coronary artery. However, when the blockage is too large, a delivery catheter cannot access the desired insertion site.
In addition, it is often difficult to advance devices into the myocardium because of the traction and force necessary to push through the myocardium. This problem arises not only for delivery of the stent, but also for the delivery of dilation catheters used to expand the cross-section of the passageway through the myocardium, and other devices.
Accordingly, what is needed is a method and apparatus for delivering guidewires, stents and other devices into the myocardium. In particular, what is needed is a delivery system that can deliver these devices at an angled bend for transverse insertion into the myocardium. Moreover, what is needed is a delivery method and apparatus for advancing a delivery catheter to a puncture site in a coronary vessel when the blockage in the vessel is too large to permit passage of a catheter therethrough. What is also needed is a method and apparatus for advancement of a stent, dilation catheter or other device into and through the myocardium.
Briefly stated, the present invention addresses the above needs by providing various methods and apparatuses for delivering stents and other devices into the myocardium of a patient. One preferred stent delivery system provides access to the insertion site in the myocardium by advancing a delivery catheter through a blockage in a coronary artery, or around the blockage through a coronary vein or through a channel or tunnel formed around the blockage. In one embodiment, once the distal end of the delivery catheter is adjacent the myocardium, an angled bend is created in the catheter by actuating expandable steering guides mounted to the catheter which cooperate with the walls of the blood vessel to cause the catheter to turn. Then, a guidewire is advanced through the delivery catheter and into the myocardium. In another embodiment, a tip-deflecting pull wire extends from the distal end of the delivery catheter which may be actuated to turn towards and then inserted into the myocardium. In another embodiment, an exit port facing the insertion site is provided within the catheter or a balloon mounted on the catheter so that a guidewire may be directed through a lumen and out the exit port into the myocardium. Once the guidewire punctures into the myocardium, the guidewire is anchored using barbs, balloons or other actuatable members to secure the guidewire to the myocardium. Subsequently, using a push-pull mechanism, stents and other medical devices can be advanced over the guidewire into the myocardium.
In one aspect of the present invention, a guidewire is delivered into the patient such that the proximal end of the guidewire extends out of the patient, while the distal end of the guidewire is positioned adjacent the myocardium. The distal end of the guidewire is inserted into the myocardium, and the guidewire is then anchored to the myocardium. An introducer catheter carrying a medical device is advanced over the guidewire to deliver the device into the myocardium.
In another aspect of the present invention, a method for delivering a stent into the myocardium to bypass a blockage formed in a coronary artery is provided. A channel is created from a position proximal to the blockage in the coronary artery to a position distal to the blockage in the coronary artery. A guidewire is advanced through the channel until a distal end of the guidewire is adjacent the myocardium. The guidewire is inserted into the myocardium, and a stent is advanced over the guidewire into the myocardium.
In another aspect of the present invention, a method is provided for creating a bypass through the myocardium of a patient to bypass a blockage formed in a coronary artery. A first tunnel is created through the myocardium having a proximal end and a distal end. The proximal end of the tunnel opens into the coronary artery proximal to the blockage. The distal end of the tunnel is positioned within the myocardium. A second tunnel is created through the myocardium, the second tunnel having a first branch extending from the distal end of the first tunnel and opening into the coronary artery at a position distal to the blockage. A second branch of the second tunnel extends from the distal end of the first channel and opens into the left ventricle. A stent is disposed in the second tunnel to provide a myocardial passageway therethrough.
In another aspect of the present invention, a delivery catheter is provided. This delivery catheter comprises an elongate tubular body having a proximal end and a distal end and a lumen extending therethrough. A first steering member is mounted on the distal end of the tubular body, and a second steering member is mounted on the distal end of the tubular body at a position distal to that of the anchoring member.
In another aspect of the present invention, a method for turning a distal end of a catheter within a body lumen is provided. The catheter comprises an elongate tubular body having a proximal end and a distal end. An anchoring member mounted to the distal end is actuated to secure the catheter against the body lumen. A steering member is mounted to the distal end of the of the guidewire at a position distal to that of the anchoring member. When actuated, the steering member cooperates with the body lumen to turn the distal end of the catheter.
In another aspect of the present invention, a method is provided for delivering a medical device to a delivery site within a patient. This method comprises providing a delivery catheter having a proximal end and a distal end and a lumen extending therethrough into a body lumen of the patient. The delivery catheter is secured within the body lumen. The distal end of the catheter is turned by actuating a steering member mounted on the distal end of the catheter which pushes off against a wall of the body lumen. The medical device is advanced through the lumen of the delivery catheter and out the distal end.
In another aspect of the present invention, a method for delivering a stent into the myocardium of a patient is provided. A delivery catheter is advanced into the vasculature of the patient, the delivery catheter having a proximal end and a distal end and a lumen extending therethrough, until the distal end is adjacent the myocardium. A pull wire extending from the distal end of the delivery catheter is actuated to turn the pull wire toward the myocardium. The pull wire is advanced from the distal end of the delivery catheter into the myocardium. The stent is delivered over the pull wire into the myocardium.
In another aspect of the present invention, a method for delivering a stent into the myocardium of a patient is provided. A delivery catheter is advanced into the vasculature of the patient, the catheter having a proximal end and a distal end and a lumen extending from the proximal end to a side port near the distal end, until the side port faces the myocardium. A guidewire having a proximal end and a distal end is inserted into the lumen. The distal end of the guidewire is advanced through the lumen and out the side port. The guidewire punctures into the myocardium, and the stent is delivered over the guidewire into the myocardium.
In another aspect of the present invention, a method for delivering a stent into the myocardium of a patient is provided. A delivery catheter is advanced into the vasculature of a patient, the catheter having a proximal end and a distal end, until the distal end is adjacent the myocardium. An anchoring member mounted on the distal end of the catheter is expanded to secure the delivery catheter within the vasculature. A guidewire having a proximal end and a distal end is inserted through a lumen in the expanded anchoring member, the lumen extending from a proximal end of the anchoring member to a side port facing the myocardium, so that the distal end of the guidewire exits through the side port. The guidewire punctures into the myocardium, and the stent is advanced over the guidewire into the myocardium.
In another aspect of the present invention, a delivery catheter is provided. The catheter comprises an elongate body having a proximal end and a distal end. An expandable member is mounted on the distal end of the tubular body, the expandable member having a proximal end and a distal end and an exterior surface. A guide lumen extends from the proximal end of the balloon to a side port on the exterior surface of the expandable member for directing a medical device therethrough.
In another aspect of the present invention, a method for treating an aneurysm is provided. A catheter having a proximal end and a distal end is advanced to the site of the aneurysm. An expandable member mounted on the distal end of the catheter is actuated to substantially enclose the aneurysm. An embolic element is inserted through a lumen in the expandable member into the aneurysm.
In another aspect of the present invention, a method for delivering a medical device into a body tissue of a patient is provided. The method comprises inserting a guidewire having a proximal end and a distal end into the myocardium from a coronary blood vessel. The guidewire is anchored to the body tissue, and the medical device is pushed over the guidewire into the body tissue. The proximal end of the guidewire is correspondingly pulled proximally while the medical device is pushed distally in order to assist advancing the medical device through the body tissue.
In another aspect of the present invention, a delivery system for directing medical treatment at least partially into the myocardium is provided. The delivery system comprises a guidewire having a proximal end and a distal end, means for turning the distal end of the guidewire toward the myocardium, means for anchoring the guidewire to the myocardium, and a catheter carrying the medical treatment having a lumen extending therethrough for receiving the guidewire and advancing the catheter into the myocardium.
In another aspect of the present invention, a method for delivering a stent into the myocardium of a patient to bypass a blockage formed in a coronary artery is provided. The method comprises advancing a catheter having a proximal end and a distal end and a lumen extending at least partially therethrough from the proximal end to a distal opening through the coronary artery of the patient until the distal opening is past the blockage. The catheter is turned so that the distal opening faces the myocardium. A wire having a proximal end and a distal end is extended through the distal opening such that the distal end punctures into the myocardium. The distal end of the wire is anchored to the myocardium. A dilation catheter is delivered over the wire, the catheter carrying a dilation balloon on a distal end thereof, until the balloon is within the myocardium. The dilation balloon is inflated to create an opening in the myocardium. The dilation balloon is then deflated and the dilation catheter removed from the wire. A stent introducer catheter is delivered over the wire, the stent introducer catheter carrying a stent on a distal end thereof, until the stent is located within the opening in the myocardium. The stent is deployed within the opening in the myocardium.
In another aspect of the present invention, a method for delivering medical treatment into the myocardium of a patient is provided. A tubular wire is delivered into the patient, the wire having a lumen extending therethrough. The wire once delivered has a proximal end extending out of the patient and a distal end positioned adjacent the myocardium. Means for turning the distal end of the wire towards the myocardium are provided. Then, the distal end of the wire is inserted into the myocardium. Medical treatment is delivered through the lumen in the wire into the myocardium.